Notes are given on the five species of Synergus Hartig, 1840 recorded from Central and South America, including a key for their identification. A new species, S. colombianussp. nov., is described from Colombia. The new species is an inquiline of an unidentified cynipid gall on Quercus humboldtii Bonpl. (Fagaceae). Synergus colombianus is the first Synergus species recorded from Colombia and the most southerly record of this genus in the Neotropical region. The new species is closely related to S. cultratus Ritchie et Shorthouse, 1987, S. filicornis Cameron, 1883, and S. nicaraguensis Díaz et Gallardo, 1998, but differs from these species in characters that are discussed in the text.

The Chinese fauna of the mirid subfamily Isometopinae is examined. Fifteen species of Isometopinae are recorded from China, belonging to the genera Isometopus Fieber, Letaba Hesse, Myiomma Puton, and Sophianus Distant. The known species are reviewed in detail, including their citations, distributions, and host plants. Information about type material and the description of a new species, Myiomma qinlingensissp. nov., are given. Keys to the Chinese genera and species are given.

We present new information on the parasitoids (Hymenoptera: Braconidae: Aphidiinae) of aphids infesting cotton, tobacco, citrus, and cereal agroecosystems in southeastern Europe. Nineteen species are keyed and illustrated with scanning electron micrographs and line drawings. The aphidiines presented in this work have been identified from 18 aphid taxa. Furthermore, 96 original parasitoid–aphid–plant associations are presented. Cotton, tobacco, and citrus agroecosystems are connected through aphids and their parasitoids, whereas cereal agroecosystems represent a separate group of associations.

The Palearctic species Amara communis (Panzer) and Bembidion femoratum Sturm were both first reported from North America in 1992. Since that time a sizeable number of additional specimens of both species have been found, which substantially expands their known range on the continent. These records are summarized herein. The possible modes of introduction of both species are discussed within the context of other introduced insects, particularly those first found in Atlantic Canada. In the case of A. communis, the many coastal localities where it occurs would seem to indicate that it was introduced in association with transatlantic marine traffic, possibly the shipment of dry ballast. In the case of B. femoratum, the mode of introduction is less clear. Possible associations with nursery stock, dry ballast, and the movement of aircraft are all discussed.

A new genus, Adenoepicriusgen. nov., is described, with Adenoepicrius magnussp. nov. from Canada designated as type. Also described are A. oconnorisp. nov. (New York, Ontario), A. curtipilussp. nov. (Virginia), and A. virginianussp. nov. (West Virginia). A key to species based on adult females is provided.

Traits that function in male–female sexual interactions tend to diverge rapidly compared with other traits. Several hypotheses attempt to explain this evolutionary pattern. Predictions of two of these hypotheses, lock-and-key and sexually antagonistic morphological co-evolution, were tested by examining how two sets of species-specific male structures fit with female structures during courtship and copulation in the fly Sepsis cynipsea (L., 1758). Contrary to predictions of both hypotheses, neither the species-specific modifications of the male's front legs nor those of his genitalic surstyli were matched by modifications of the female structures with which they meshed (wing bases, 6th abdominal sternite); males damaged small patches of microtrichia on the female's wings with their legs, but the morphology of the female's wings and abdomen showed no sign of the defensive designs expected under antagonistic morphological co-evolution. Data regarding the alternative hypothesis of sexually antagonistic behavioral co-evolution by females in response to male morphology were less conclusive, but this hypothesis failed to explain the sustained, apparently stimulatory rhythmic squeezing by the male genitalia and the lack of female defensive responses to this squeezing. These movements of the male surstyli during copulation suggest that they function to stimulate the female. The wing base of the female has apparent sense organs near the sites contacted by the male, as expected under the alternative hypothesis of traditional female choice to explain rapid divergent evolution. The male's genitalic surstyli were also used in novel precopulatory interactions. A pair of previously undescribed processes at the bases of the surstyli probably grasp and may also rhythmically squeeze the female during copulation.

Monte-Carlo simulation was used to examine the effects of fire return rates on the equilibrium age structure of a one-million-hectare lodgepole pine forest (Pinus contorta var. latifolia Engelm. ex S. Wats.; Pinaceae) and yielded a mosaic of ages over the one million hectares for each fire regime modelled. These mosaics were used to generate mosaics of susceptibility to mountain pine beetle (MPB) (Dendroctonus ponderosae Hopkins, 1902) attack. This susceptibility was related to the age distribution to calculate the mean susceptibility of the forest. Susceptibility maps were produced for two timber supply areas in British Columbia, as well as for the whole of B.C. In addition, we defined a quality, called traversability, that describes the ability of a beetle population to disperse across a landscape according to defined rules of susceptibility and maximum distance for dispersal through unsuitable habitat. Using each of 40 combinations of susceptibility classifications and dispersal limits, the landscape was categorized as traversable or non-traversable. This represents the suitability of a landscape to the unimpeded spread of an incipient beetle population. It was found that (i) long fire cycles yield an age structure highly susceptible to beetle attack; (ii) fire suppression reduces the frequency of fires and yields an age structure highly susceptible to beetle attack; and (iii) harvesting one age class reduces the mean susceptibility to MPB attack, and this reduction decreases with increasing harvest age and increasing fire cycle length. When fires were limited in size to less than 100 ha, the area was always traversable. For larger fires, traversability declined, and for the largest fires (up to one million hectares), the area was often not traversable. Harvesting reduced the mean susceptibility and traversability, often substantially. Traversability was calculated for the whole of B.C. in blocks of about one million hectares using B.C. Ministry of Forests and Range inventory data for the year 2000. The area most traversable was the area around Tweedsmuir Park and the Lakes Timber Supply Area, where most of the present outbreak of MPB is centred. FRAGSTATS patch metrics were calculated for each of the simulations and were related to traversability using discriminant analysis. This analysis was then applied to the B.C. inventory; the concordance was high, with 93.3% of conditions being correctly classified.

Breeding experiments and rearing under variable controlled conditions have revealed that western and 2-year-cycle spruce budworms (Choristoneura occidentalis Freeman and C. biennis Freeman, respectively) from British Columbia, Canada, and their hybrid progeny have the inherent capacity for a variable number of diapause events and hence voltinism. While all crosses have at least one diapause, variability in the relative frequency of a second diapause is determined by genetic traits modified by the photoperiod and, to a lesser extent, temperature experienced during the larval stages. Second diapause appears fixed in C. biennis but is facultative and most frequent at short photophases (12L:12D) in C. occidentalis. Hybrids and backcrosses had responses intermediate to the parental responses under all environmental conditions. The occurrence of a facultative third diapause in all crosses underlines the inherent capacity for flexibility in voltinism in these species. These results are discussed in the context of past, present, and future distributions of alternative life cycles in closely related species.

Plant bugs, species of the genus Lygus Kelton (Hemiptera: Miridae), damage many crops in western Canada (Kelton 1980; Wise and Lamb 1998; Wise et al. 2000). Lygus lineolaris (Palisot de Beauvois), L. borealis (Kelton), and L. elisus Van Duzee are the most common species in the eastern prairie of Canada (Schwartz and Foottit 1992). Manitoba is the leading producer of buckwheat, Fagopyrum esculentum Moench (Polygonaceae), in North America, growing about 15 000 ha annually (Canada Grains Council 1999). Plant bug adults are known to oviposit (Painter 1927) and feed on buckwheat (Bugg and Ellis 1990), but little is known about their ability to develop on this crop. The objectives of the study were to determine (i) the species of plant bugs on buckwheat, (ii) their ability to develop on buckwheat, and (iii) the distribution of plant bugs within commercial fields of buckwheat in Manitoba.

The wheat stem sawfly, Cephus cinctus Norton, is the most important insect pest of dryland wheat, reducing both harvest efficiency and head weight. When wheat lodged (flattened) by C. cinctus is straight-cut, harvest efficiency is affected in three ways: (1) lodged stems are difficult to collect with the combine, so mature wheat is lost; (2) the combine has to operate more slowly to collect as many of the lodged stems as possible; and (3) there is increased risk of damage to the combine due to lowering of the combine header to recover lodged stems. An alternative harvest method is to swath the wheat before lodging occurs and place it in windrows prior to combining. When swathing is used, harvest efficiency is not affected by the C. cinctus infestation level; however, this type of harvesting is more expensive and labor-intensive than straight- cutting. Thus, swathing should be used only when the crop is heavily infested by C. cinctus, while straight-cutting should be used when the level of C. cinctus infestation is lower. Adapting harvesting practices to the C. cinctus infestation level requires a sampling plan that can reliably and cost-effectively predict the infestation level in a given field. In this study, we (i) evaluate the relationship between sampling effort along field edges and precision of the estimated average infestation level in 6 wheat fields, and (ii) generate a Gaussian regression analysis of the infestation level up to 200 m into 18 wheat fields using two variables, distance from the edge and average infestation level at the edge, as explanatory variables. We conclude that little additional precision for estimates of infestation level is gained by collecting more than 10 samples along field edges. We also conclude that the average C. cinctus infestation level along field edges can be used successfully to predict infestation levels up to 200 m into winter wheat fields. The proposed sampling should be implemented about one month before harvest to provide growers with enough time to make logistical preparations for harvest.

Trembling aspen, Populus tremuloides Michx. (Salicaceae), is the most widely distributed tree species in North America (Perala 1990) and is considered to be an ecologically (Hogg et al. 2002) and economically important (Brandt et al. 2003) component of the boreal forest. Due to the recently increased economic value of trembling aspen (Brandt et al. 2003), the impact of native insect defoliators on tree growth and mortality has become commercially important. Two of the most significant defoliators of trembling aspen throughout its range in Canada are the forest tent caterpillar (FTC), Malacosoma disstria Hübner (Lepidoptera: Lasiocampidae), and the large aspen tortrix (LAT), Choristoneura conflictana Walker (Lepidoptera: Tortricidae).

The Holarctic genus Chrysoclista (Lepidoptera: Agonexenidae) consists of very distinctive, small, brightly coloured moths whose larvae bore in the bark of deciduous trees. There are seven species worldwide including three found in Europe, two found in the Caucasus, and two Nearctic species, C. cambiella (Busck, 1915) and C. villela (Busck, 1904). In addition, the Palearctic species C. linneella (Clerck, 1759) has been introduced to North America (Karsholt 1997).

In Europe, C. linneella is found across most of the continent, in all of the Baltic and Fennoscandian countries, Great Britain, the Netherlands, Belgium, Luxembourg, Germany, Poland, Czech Republic, Slovakia, Hungary, Austria, Switzerland, France, Spain, Italy, Rumania, Russia (Karsholt and Razowski 1996), Turkey, and Ukraine (S. Koster, personal communication).

The hemlock woolly adelgid (HWA), Adelges tsugae Annand, is the number one threat to hemlock (genus Tsuga Carr.; Pinaceae) forests in eastern North America. Sasajiscymnus tsugae (Sasaji et McClure), an introduced coccinellid from Japan, is a promising biological control agent for HWA. In mass rearing of S. tsugae, the main goals are to maximize adult beetle production, reduce the amount of human labor, and minimize production costs. Significantly higher adult S. tsugae production and survivorship from egg to adult were observed in a modified rearing box compared with a conventional rearing box. The 30 modified boxes produced 4400 more beetles than the 30 conventional boxes. Over time, egg to adult survivorship decreased because of larval cannibalism at densities above 1650 larvae per rearing box. Additionally, warmer weather conditions increased the number of insect and spider predators incidentally introduced via HWA-infested hemlock twigs. There was no significant difference in the time required to prepare modified and conventional boxes for initial introduction of eggs, but significantly less time was required to add water, honey, and HWA-infested twigs to the modified boxes. The additional cost and time required to add modifications to each box was compensated for by the increased number of adult S. tsugae produced and the time saved during the 35 days of scheduled maintenance as eggs hatched and larvae developed to adults.